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In arid and semi-arid climates, water scarcity and nutrient availability are major constraints for food production. Excess fertilization to make up for the limited nutrient availability in dry soils leads to nitrogen runoff and groundwater contamination. Reducing nitrogen leaching into surface water while providing adequate nutrition remains a major challenge. Superabsorbent polymers (SAPs) can reduce water loss and improve nutrient retention and therefore minimize leaching and increase crop yields. SAPs are made from petroleum or natural products, but plant-based SAPs have been gaining popularity because they have fewer long-term effects on the environment. However, there is little known about how SAPs made from cornstarch effect plant growth and production in tomatoes. So, we evaluated total nitrogen and water retention in SAP-treated soils and evaluated their effects on growth and development of tomatoes (Solanum lycopersicum). Soils were amended with different rates of cornstarch-based SAP (i.e., 0 kg SAP, 0 kg SAP+N, 0.5 kg SAP+N, 1 kg SAP+N, 1.5 kg SAP+N, and 2 kg SAP+N). Results indicate that the mean volume of water and nitrates retained in the soils amended with cornstarch-based SAPs increased with increasing rate of SAP. The treatment containing the highest dose (i.e., 2 kg SAP) decreased the amount of leachate and nitrates from soil 79.34% and 93.11% at 3 days after fertilization (DAF) and 78.84% and 81.58% at 9 DAF in comparison with the soil-only and fertilizer-only treatments, respectively. The results also indicate cornstarch-based SAP significantly improved plant growth and yield parameters compared with the treatments without SAP. Furthermore, the greatest number of leaves, flowers, fruits, and dry matter production were found in the 1-kg SAP treatment. Therefore, application of cornstarch-based SAPs can improve tomato production in times of drought stress by retaining more water and nutrients in the active rooting zone and can reduce environmental pollution by reducing nitrogen runoff.

The aim of this study was to assess the potential use of biochar derived from olive pruning to enhance soil properties and tomato and bell pepper plant growth and yield performance in arid environments. Biochar was prepared from olive tree–pruning residues. The biochar was applied to field experiments of tomato and bell pepper plants at five application rates (0, 8, 16, 30, and 40 t ha−1). Relative water content (RWC), leaf chlorophyll, and leaf nutrient (nitrogen (N), phosphorus (P), and potassium (K)) contents were measured. The total yield was determined for each treatment. Fruit nutrient contents were determined in selected fruit samples. Soil samples were collected from each treatment at the middle and end of the experiment for physical and chemical analysis. All experiments were conducted in triplicate. The application of biochar at rates of 8 and 16 t ha−1 enhanced tomato and bell pepper growth; however, application of 30 and 40 t ha−1 adversely affected tomato and bell pepper growth. Nutrient analysis showed that N, P, and K concentrations in leaves and fruits were higher in plants treated with 8 and 16 t ha−1 of biochar than in biochar treatments of 30 and 40 t ha−1. Higher biochar application rates increased soil pH and EC by 1.4% and 12.3% (8 t ha−1) to 7.3% and 107.8% (40 t ha−1), respectively. A biochar application rate of 8 t ha−1 is recommended as an optimal rate to enhance soil fertility for tomato and bell pepper production systems in arid environments.

Sustainable agriculture, characterized by farming profitably while minimizing damage to the environment, is not easy to practice. “Conventional agriculture” worldwide is commonly considered to involve numerous practices that have potential to damage the environment. “Sustainable agriculture” attempts to find a range of conservation agricultural practices which may mitigate some of the adverse impacts of land use intensification. Among the wide range of the conservation agricultural practices, biochar may prove a key and accessible input for sustainable agriculture, as it could efficiently sequester large amount of carbon in soil over the long-run, thus improving soil fertility, crop productivity, and mitigate global warming. In addition, biochar may enhance crop productive capacity of soils under different biotic and abiotic stresses, and advance global food security. The main focus of this report is providing a critical scientific review of the current state of knowledge regarding the effects of biochar application to soils on soil properties, processes and functions. Wider issues, including atmospheric emissions and occupational health and safety associated to biochar production and handling, are put into context. The aim of this review is to provide a sound scientific basis for policy development, to identify gaps in current knowledge, and to recommend further research relating to biochar application to soils.

Passive and active interactions with nature reduce stress, anxiety, and depression. Populations that experience increased stress often have fewer interactions with nature due to many factors. More recently, the COVID-19 pandemic has created a new stressor for all populations due to sickness, isolation, financial burdens, or other factors. University students were particularly impacted due to the change to online modalities, which isolated them from other students. To assess if any negative or other consequences were experienced and if nature factors could mitigate them, we examined how plant interactions affected university students (N = 353) in an online learning environment. Two modified Depression Anxiety Stress Surveys (DASS; Depression Anxiety Stress and Academic Stress, DASA) were administered over two semesters in 2020 to survey students on these interactions with nature. During the two semesters, most students experienced extremely severe self-reported mental health adversities. Further correlations between DASA scores and responses about nature interactions, home environments, plant exposure, and plant access showed that outdoor interactions were positively related to better self-reported mental health scores. However, the concerning and lingering effects of the pandemic were evidenced in our research as DASA scores increased across the two semesters. Nevertheless, going outdoors and interacting with nature brings some benefits that lessen the severity of depression, anxiety, and stress.

Partial rootzone drying (PRD) has been reported to potentially improve crop water use efficiency (WUEcrop) compared to full irrigation in different fruit trees; however, field studies on the effect of PRD in citrus are scarce. In this field study, three irrigation strategies were tested in an orchard of mature grapefruit trees during two consecutive seasons (2013/2014 and 2014/2015): drip PRD (two drip lines, alternating irrigation between lines every month), microsprinkler irrigation, and double-line drip irrigation (control). Irrigation was applied during the fruit enlargement stage (April–August). The aims of this field study were: 1) to provide a quantitative comparison of irrigation water productivity among irrigation treatments; and 2) to study their effects on fruit quality, yield, tree growth, and flowering. Drip PRD saved 43 to 47% of irrigation water compared to control irrigation, and microsprinkler irrigation saved 12 to 18% of water compared to control irrigation PRD-irrigated trees maintained or increased yield compared to microsprinkler-irrigated and control trees, depending on the experimental season. Therefore, WUEcrop in PRD-irrigated trees was significantly higher than in control and microsprinkler-irrigated trees at the end of both seasons. Fruit and juice quality parameters were statistically similar among all treatments. PRD irrigation did not reduce the flowering potential of the trees although it delayed the onset of flowering in trees relative to the other treatments in 2013/2014. There was a similar timing of flowering among treatments in 2014/2015 and there were no differences in vegetative growth among the irrigation treatments by the end of March (86 Julian data) in both experimental seasons. Our results suggest that PRD can be economically beneficial for citrus growers who use double-line drip irrigation systems, and a strategy to sustain tree growth, tree health and yield during seasons of extreme drought or when high water restrictions are placed in citrus-producing areas.

High temperatures and drought are common stresses limiting crop growth and productivity in subtropical regions where citrus are produced. In addition to impacts on physiological processes such as transpiration, photosynthesis, and respiration, excessive solar radiation can also reduce fruit productivity by inducing physiological disorders such as sunburn. This study evaluated the effects of radiation reflectants and anti-transpirants on leaf physiology, and fruit sunburn in grapefruit trees (Citrus x paradisi Macfs. cv. Rio Red) in south Texas during the 2016 and 2017 growing seasons. Two calcium-based reflectants, and a methene/pinolene-based anti-transpirant were foliar applied to fruit-bearing trees. Reflectants reduced fruit and leaf temperatures by 0.2&deg, C and 0.21&deg, C, respectively, while the anti-transpirant treatments increased fruit and leaf temperature by approximately 0.83&deg, C and 0.2&deg, C relative to the controls. Stomatal conductance decreased by 1.3% and 3.3%, respectively, in response to the reflectant treatments, while anti-transpirant treatments resulted in decreased stomatal conductance (8.3%) relative to the controls. More sunburned fruit were found in anti-transpirant treated trees in both years (6% and 8.2% for 2016 and 2017) and the reflectant treatments reduced sunburn incidence by 4.9% and 1.8% in those years. These observations indicate that reflectant applications could be a viable strategy to mitigate heat/radiation stress and sunburn in grapefruit.

Waterlogging occurs because of poor soil drainage and/or excessive rainfall and is a serious abiotic stress affecting plant growth because of declining oxygen supplied to submerged tissues. Although cucumber (Cucumis sativus L.) is sensitive to waterlogging, its ability to generate adventitious roots facilitates gas diffusion and increases plant survival when oxygen concentrations are low. To understand the physiological responses to waterlogging, a 10-day waterlogging experiment was conducted. The objective of this study was to measure the photosynthetic and key metabolites of cucumber plants under waterlogging conditions for 10 days. Plants were also harvested at the end of 10 days and analyzed for plant height (ht), leaf number and area, fresh mass (FM), dry mass (DM), chlorophyll (Chl), carotenoid (CAR), proline, and soluble sugars. Results indicated that cucumber plants subjected to the 10-day waterlogging stress conditions were stunted, had fewer leaves, and decreased leaf area, FM, and DM. There were differences in physiological performance, Chl, CAR, proline, and soluble sugars. Overall, waterlogging stress decreased net photosynthesis (A), having a negative effect on biomass accumulation. However, these decreases were also dependent on other factors, such as plant size, morphology, and water use efficiency (WUE) that played a role in the overall metabolism of the plant.

Subtropical and tropical climates are becoming more vulnerable to drought and salinity problems. Of the crops produced in these climates, citrus is especially sensitive to increasing salinity. In times of water scarcity and periodic drought alternative water sources that may be lower in quality may be required for irrigation, leading to reduced yield unless a mechanism of increasing salinity tolerance is found. The salinity tolerance of citrus rootstocks differs depending on species and cultivar in their ability to exclude or sequester toxic ions. Identifying rootstocks that are more salt tolerant is important to citrus production in susceptible areas. ‘Olinda’ Valencia trees budded to three rootstocks (sour orange [SO], C22, and C146) and the ungrafted rootstocks were subjected to 6 months of saline irrigation. Simulated brackish water at 1, 3, 5, and 10 dS m −1 along with a 0 dS m −1 control were used to irrigate trees over the course of the study. Throughout this time period chlorophyll fluorescence, stomatal conductance, electrolyte leakage, and SPAD were measured to identify how trees responded to different levels of salinity stress. Chlorophyll fluorescence, stomatal control, and SPAD decreased with increased salinity, while electrolyte leakage increased. These responses were more pronounced in grafted trees than ungrafted trees. C22 and C146 rootstocks showed more tolerance to increases in salinity than the SO rootstocks. The ‘Olinda’ Valencia scion reduces rootstock tolerance to salinity, however, trees grafted to the C22 and C146 rootstocks showed more salinity tolerance than those grafted to SO rootstocks. This study emphasizes that both rootstock and scion should be considered when selecting trees for saline conditions.

Grove floor management practices play a significant role in citrus physiology, root distribution, and overall tree health. Among the various agricultural practices evaluated in this study, black plastic mesh groundcovers showed increasing soil moisture availability and temperature, as well as improving plant growth and yields. Raised bed practices have also been used to increase soil drainage and porosity to promote root proliferation in compacted soils. While these practices have been primarily studied on annual or row crops, their introduction into grove systems has been slow, even the positive results obtained with these practices. Citrus are managed very differently from row crops, with long-term practices and management techniques often negatively impacting root growth. Citrus management practices using raised beds and black plastic mesh groundcovers have shown great promise in improving citrus production and tree growth. However, few studies have investigated the impact of these practices on root growth and morphology and how these practices affect aboveground growth and production. In this experiment, we aimed to evaluate how different practices affected root growth and how this, in turn, impacted aboveground parameters. To accomplish this, we examined root distribution and in-growth (root growth inside a hand-made core) in four different citrus grove floor management systems; raised bed with groundcover, raised bed without groundcover, flatbed with groundcover, and flatbed without groundcover at various times throughout the growing season for three years. We then assessed how each treatment parameter affected root characteristics and how this affected the aboveground and soil measurements. Root analysis with WinRhizo® software showed significant differences between management systems. Raised beds with black plastic groundcovers increased root growth and density throughout the study. Seasonal in-growth core data indicated that the period from Fall-Spring showed significantly higher root growth than the Spring-Fall period, indicating seasonal growth and senescence of roots. The Spring-Fall cores were also less influenced by management treatment than the other sampling dates. While short-term growth varied with season, the effects of raised beds with plastic groundcovers positively influenced tree growth, root growth, and morphology over the long-term.

Salinity and drought are among the greatest threats hindering global food security. Over the last decade, biochar use in agriculture has received increasing attention and enhancing biochar through composting and chemical modification offers a potential strategy for improving soil productivity. However, there is limited knowledge on how residual sulfur-enhanced biochars alone, or in combination with effective microorganisms (EMs) impact on soil properties, and how this influences agricultural productivity in the short and long-term. To investigate this, a field experiment was conducted in 2017 to study the effect of residual sulfur-enhanced biochar (RSBC). A 5:100 (w/w) mixture of elemental sulphur (S) and citrus wood biochar (BCH), respectively combined with EMs was applied to soil. The effects on soil properties, growth, and productivity of salt-stressed pepper plants was then evaluated to determine if supplementation with RSBC and/or EMs bio-protected plants could mitigate the deleterious effects of soil salinity. These applications resulted in several beneficial effects which included: improving dehydration tolerance, nutritional status, and photosynthetic efficiency, while significantly reducing Na+ and Cd2+ concentrations in plants. The integrated RSBC + EMs treatment significantly increased plant growth, and productivity, macro- and micro-nutrient concentration, as well as, dehydration tolerance and irrigation use efficiency. A reduction in Na+ and Cd2+ uptake was also observed in conjunction with a concomitant increase in N, P, K+, Ca2+, Fe, Mn, Cu and Zn uptake. Overall, applications of residual sulfur-enhanced biochar combined with effective microorganisms show short-term beneficial effects on peppers can be attained in the presence of high salinity. This study opens up a wide avenue for research exploration; subsequent studies to examine the benefits of long term or repeated applications and could yield even more positive applications or results.

Huanglongbing (HLB) and Phytophthora foot and root rot are diseases that affect citrus production and profitability. The symptoms and physiological changes associated with these diseases are diagnosed through expensive and time-consuming field measurements. Unmanned aerial vehicles (UAVs) using red/green/blue (RGB, true color) imaging, may be an economic alternative to diagnose diseases. A methodology using a UAV with a RGB camera was developed to assess citrus health. The UAV was flown in April 2018 on a grapefruit field infected with HLB and foot rot. Ten trees were selected for each of the following disease classifications: (HLB-, foot rot−), (HLB+, foot rot−), (HLB-, foot rot+) (HLB+, foot rot+). Triangular greenness index (TGI) images were correlated with field measurements such as tree nutritional status, leaf area, SPAD (leaf greenness), foot rot disease severity and HLB. It was found that 61% of the TGI differences could be explained by Na, Fe, foot rot, Ca, and K. This study shows that diseased citrus trees can be monitored using UAVs equipped with RGB cameras, and that TGI can be used to explain subtle differences in tree health caused by multiple diseases.

Saline irrigation water can lead to salt buildup and reduced crop yields. Halophytic plants are known to accumulate excess salts in tissues, removing them from the immediate environment. This two-phase experiment explored the feasibility of intercropping watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai var. lanatus) with halophytic species to mitigate the negative effects of saline irrigation water while providing a value-added crop. In the first experiment, six greenhouse-grown species were irrigated with water that was either deionized (0 dS m−1) or contained 3 or 6 dS m−1 of salts for 41 days and screened for growth and salt removal. Two halophytes were selected to be additively intercropped with watermelon under field conditions and irrigated with the same saline irrigation levels as the first experiment. Results indicated that garden orache (Atriplex hortensis L.) exhibited the highest growth rates and purslane (Portulaca oleracea L.) accumulated high amounts of sodium in plant tissues under saline irrigation. The field experiment showed that watermelon yields, stem water potential, and fruit quality were not affected by saline irrigation; however, the watermelon/orache intercropping treatment had significantly higher yields. These results suggest intercropping with halophytes has the potential to contribute a value-added crop without reducing watermelon yields.

Huanglongbing is a devastating disease of citrus. In this study, a comprehensive profile of phloem sap amino acids (AA) in four permissive host plants of Candidatus Liberibacter asiaticus (CLas) and three non-permissive Rutaceae plants was conducted to gain a better understanding of host factors that may promote or suppress the bacterium. The AA profiles of Diaphorina citri nymphs and adults were similarly analyzed. A total of 38 unique AAs were detected in phloem sap of the various plants and D. citri samples, with phloem sap of young shoots containing more AAs and at higher concentrations than their mature counterparts. All AAs detected in phloem sap of non-permissive plants were also present in CLas -permissive hosts plus additional AAs in the latter class of plants. However, the relative composition of 18 commonly shared AAs varied between CLas -permissive hosts and non-permissive plants. Multivariate analysis with a partial least square discriminant methodology revealed a total of 12 AAs as major factors affecting CLas host status, of which seven were positively related to CLas tolerance/resistance and five positively associated with CLas susceptibility. Most of the AAs positively associated with CLas susceptibility were predominantly of the glutamate family, notably stressed-induced AAs such as arginine, GABA and proline. In contrast, AAs positively correlated with CLas tolerance/resistance were mainly of the serine family. Further analysis revealed that whereas the relative proportions of AAs positively associated with CLas susceptibility did not vary with host developmental stages, those associated with CLas tolerance/resistance increased with flush shoot maturity. Significantly, the proline-to-glycine ratio was determined to be an important discriminating factor for CLas permissivity with higher values characteristic of CLas -permissive hosts. This ratio could be exploited as a biomarker in HLB-resistance breeding programs.

As population and agricultural pressure on high quality fresh water resources increases, it becomes more important to identify rootstocks and production techniques that allow the usage of lower quality water in irrigated agriculture. Water of 0, 1, 3, 5 and 10 dS m −1 salinity was applied to grafted (with Olinda Valencia ( Citrus sinensis var. Olinda) scion) and ungrafted sour orange ( Citrus aurantium L.), C22, and C146 ( Citrus sunki Hort. Ex Tan. × Poncirus trifoliata L. Raf. ‘Swingle’) trees to evaluate the effect of grafting and rootstock variety on salinity tolerance. Grafted rootstocks had a lower survival rate at higher salinity concentration than ungrafted trees and effects were dependent upon tree variety. Height growth rate and standing leaf area of grafted citrus trees declined with increased salinity concentrations while the response of ungrafted and grafted citrus trees was variety dependent. Mortality increased and standing leaf area decreased with increasing tissue Na + and Cl − concentrations. Mortality in response to salinity was greater in grafted rootstocks than mortality of ungrafted trees. Overall, C22 and C146 rootstocks and ungrafted trees were found to be more tolerant of saline conditions than grafted SO rootstock or ungrafted SO trees.

Improving sustainable citrus production through soil and water conservation strategies such as plastic mesh groundcovers and raised planting beds has not been thoroughly evaluated. To determine the impacts of these practices on tree growth parameters, fruit yield, and soil environmental conditions we monitored a grapefruit grove (Citrus paradisi Macf. cv.‘Rio Red’) for five years after planting. Trees were planted under four grove floor management strategies that included flat beds with no plastic mesh groundcover (traditional practice), flat beds with groundcover, raised beds with no groundcover, and raised beds with groundcover. The use of ground cover increased soil temperature and moisture content and led to higher tree growth rates and yields relative to uncovered grove floors. Raising the planting bed to approximately 45 cm higher than the surrounding field reduced soil deposition from irrigation and improved soil properties, but caused fluctuations in soil moisture due to improved water infiltration of heavy clay soils compared to the flat beds. Despite the positive effects of the use of ground cover on yields, there was a trend of alternate bearing, smaller and sweeter fruit sizes for trees under this planting design. The traditional method of planting (flat bed with no groundcover) resulted in smaller trees as measured by tree height, canopy circumference, and trunk diameter. While yields were moderate, they were fairly consistent across years and increased slightly each year of the study. These results show that adoption of plastic mesh groundcovers in citrus or other tree fruit production could potentially improve water conservation while increasing production.

Studies were conducted to relate the influence of the physical characteristics, leaf nutrient content and phloem sap amino acid concentration of citrus flush shoots on the densities of various Diaphorina citri life stages. Adult D. citri preferentially selected young shoots for feeding and numbers of D. citri immatures were positively correlated with flush shoot softness. Young flush shoots had higher concentrations of macro and micro nutrients relative to mature ones and this was associated with higher densities of all D. citri life stages. All D. citri life stages were positively correlated with higher nitrogen-carbon (N:C), nitrogen:sulfur (N:S) and nitrogen:calcium (N:Ca) ratios in leaf tissue, while densities of adults were negatively related to calcium, manganese and boron levels. Concentrations of total and essential amino acids were highest in phloem sap of young expanding flush shoots in both grapefruit and lemon, but dramatically declined as flush shoots matured. The sulfur-containing amino acids cystine, methionine and taurine occurred only in younger flush shoots. In contrast, cystathionine was only present in phloem sap of mature shoots. These results clearly indicate that young citrus flush shoots are a nutritionally richer diet relative to mature shoots, thus explaining their preference by D. citri for feeding and reproduction. Conversely, tissue hardness and the lower nutritional quality of mature flush shoots may limit oviposition and immature development. The data suggest that both physical characteristics and nutritional composition of flush shoots and their phloem sap are important factors regulating host colonization and behavior of D. citri, and this interaction can impact the dynamics and spread of HLB in citrus groves.

BACKGROUND: Metam-sodium (MS, sodium methyldithiocarbamate) has been identified as a promising alternative chemical to replace methyl bromide (MeBr) in soil preplant fumigation. One degradation product of MS in soil is the volatile gas methyl isothiocyanate (MITC) which controls soilborne pests. Inconsistent results associated with MS usage indicate that there is a need to determine cultural practices that increase pest control efficacy. Sealing the soil surface with water after MS application may be a sound method to reduce volatilization loss of MITC from soils and increase the contact time necessary for MITC to control pests. The objective of this research was to develop a preliminary soil surface water application amount that would potentially inhibit the off-gassing rate of MITC. RESULTS: Off-gassing rate was consistently reduced with increasing water seal application. The application of a 2.5–3.8 cm water seal provided significantly lower (71–74% reduction in MITC volatilization) total fumigant loss compared with no water seal. The most favorable reduction in MITC off-gassing was observed in the 2.5 cm water seal. CONCLUSION: This suggests that volatilization of MITC-generating compounds can be highly suppressed using adequate surface irrigation following chemical application in this soil type (sandy clay loam), based on preliminary bench-scale soil column studies. Copyright © 2010 Society of Chemical Industry

The banning of methyl bromide (MeBr) as a pre-plant soil fumigant due to its implication as an ozone depleting substance, has led to increased interest in finding alternative soil fumigants to replace MeBr (United States Environmental Protection Agency [USEPA], 2009). One of the promising alternatives for certain crops is methyl isothiocyanate (MITC). Several MITC generating compounds, such as metam sodium®, metam potassium®, and dazomet® are being used to control a wide variety of fungal pathogens, weeds, and nematodes in soils. The physiochemical characteristics of MITC are significantly different than that of MeBr, such as that its effectiveness in regards to dissipation and movement in the soil is altered by multiple factors, such as soil type, texture, and soil moisture content. The largest challenge to soil fumigation is the prevention of fumigant loss to the atmosphere and especially to the nearby communities and homes adjacent to farm land. Rapid off-gassing or non-target release of the fumigant to the atmosphere can lead to poor pesticide performance and ineffective pest control. To combat this problem that is common to all soil fumigants currently on the market, various methods have been employed to reduce chemical offgassing. A few of these methods are tarping the soil surface immediately following chemical application with high density polyethylene plastic, incorporation of organic matter to the soil surface to absorb the fumigant, or altering chemical formulations. Another method of reducing fumigant loss can be applying a surface water application as a means of sealing the soil surface to prevent chemical volatilization. On-farm field scale studies have been performed to evaluate all of these methods to better evaluate the potential for reducing fumigant loss to the atmosphere. However, field-scale studies are expensive to perform, and experimental error is challenging to control and replicate due to diurnal temperature fluctuations, varying soil physical properties, and air current differences. Thus, the volatilization loss in one study will not represent the typical fumigant loss from site to site. A more controlled laboratory environment is needed to more adequately predict fumigant loss under specific conditions. Laboratory-scale columns can be used to study soil fumigant release from soils under a wide array of conditions and under controlled

Metam-sodium (MS, sodium methyldithiocarbamate) has been identified as a promising alternative chemical to replace methyl bromide (MeBr) in soil preplant fumigation. One degradation product of MS in soil is the volatile gas methyl isothiocyanate (MITC) which controls soilborne pests. Inconsistent results associated with MS usage indicate that there is a need to determine cultural practices that increase pest control efficacy. Sealing the soil surface with water after MS application may be a sound method to reduce volatilization loss of MITC from soils and increase the contact time necessary for MITC to control pests. The objective of this research was to develop a preliminary soil surface water application amount that would potentially inhibit the off-gassing rate of MITC.Off-gassing rate was consistently reduced with increasing water seal application. The application of a 2.5-3.8 cm water seal provided significantly lower (71-74% reduction in MITC volatilization) total fumigant loss compared with no water seal. The most favorable reduction in MITC off-gassing was observed in the 2.5 cm water seal.This suggests that volatilization of MITC-generating compounds can be highly suppressed using adequate surface irrigation following chemical application in this soil type (sandy clay loam), based on preliminary bench-scale soil column studies. .